Movies don't have to be good to be influential. Take "Blood Feast." Before its 1963 release, horror films showed brutality and violent murder with only occasional glimpses of blood, quickly looking away when the mayhem grew too graphic. Director Herschell Gordon Lewis and producer David F. Friedman changed all that in 1963 by making an ultracheap movie with virtually no script [source: Weber]. The entire point of the movie was to show as much gruesome gore and blood as possible. They knew that they could show audiences something they'd never seen before, and they hoped that would translate into profit (it certainly did, making at least $7 million on a budget that barely exceeded $20,000) [source: Abrams].

The stage tradition of grotesque violence known as Grand Guignol had always appealed to audiences looking for a thrill, but it had never been done on film. "Blood Feast" was the first splatter movie, a movie made specifically to show disgusting, bloody things on screen. Legs are chopped off, brains splashed on the floor and a woman's tongue is pulled from her mouth. Every scene is bathed in vibrant, red stage blood. It forced film censorship boards to redefine how they treated film violence while paving the way for graphic violence to leak into the mainstream.

Inspired by "Blood Feast," a generation of special effects fans devoted themselves to creating ever more realistic and bloody effects. There's an entire gore subgenre, mixed liberally with the slasher genre (which we'll talk about shortly).